Archive for shellfish

A parasitic isopod known as Orthione griffenis is decimating mud shrimp populations in coastal estuaries ranging from British Columbia to northern California. Most surviving mud shrimp populations are heavily infested with the parasite, threatening their existence.

“From Bamfield, Canada, down to Morro Bay, California, the native mud shrimp, Upogebia pugettensis, are either gone or the populations are severely depressed,” said John Chapman, an Oregon State University invasive species specialist who works out of OSU’s Hatfield Marine Science Center in Newport.

Mud shrimp are valuable prey for birds, fish and other animals in estuaries, and some ecologists believe they have provided a steady food source for ocean-bound juvenile coho and Chinook. Mud shrimp are also important to the ecology of estuaries: each day during their feeding, they may filter as much as 80 percent of the estuary’s intertidal water.

Studying the shrimp, which can burrow to depths of two meters, involves extracting them with quantitative sampling devices. These devices traditionally have been either handheld cores and shovels, which can damage the shrimp beds, or a “yabby” pump, which sucks up only medium-sized and large shrimp and is not quantitative. Neither method is reliable for quantifying the most important reproductive sizes, and both often damage shrimp in the process of collecting them.

The solution? Create a new device that’s not only long enough to reach the deepest shrimp, but gentle enough to bring them to the surface unharmed — and also simple enough to allow for rapid, inexpensive sampling by just a few researchers.

To develop the device — a “portable deep core” — Chapman enlisted the assistance of OSU Engineering professors John Parmigiani and Sharon LaRoux, who would oversee the student design teams* and participate in the field testing and implementation. Chapman and Parmigiani also secured $9,000 in funding from Oregon Sea Grant, to help defray materials costs and other expenses.

Between January and May 2017, three student teams, each working on a different design, researched, planned, designed, built and tested the components of their respective devices, and on May 19 they unveiled the working prototypes at OSU’s Undergraduate Engineering Expo. “Each of the three designs will be evaluated and combined over the summer by a graduate student into a single, final prototype,” said Parmigiani.

According to Chapman, the newly designed deep core “will, for the first time, give us access to the entire range of burrowing shrimp populations, and let us gather the information we need to help slow or reverse the mud shrimp’s decline.”

The Hermes Creative Awards are administered and judged by the Association of Marketing and Communication Professionals. According to Hermes, “AMCP judges are industry professionals who look for companies and individuals whose talent exceeds a high standard of excellence and whose work serves as a benchmark for the industry.”

This year’s competition attracted about 6,000 entries from around the United States, Canada and numerous other countries, according to Hermes.

The public may not be convinced that ocean acidification is a problem, but a growing number of those who make their living off the ocean have become believers.

A new Oregon Sea Grant-funded survey, being published this week in the Journal of Shellfish Research, found that more than 80% of respondents from the US West Coast shellfish industry are convinced that acidification is having consequences – a figure more than four times higher than found among the broader public, researchers say. And about half the industry people surveyed reported having experienced some impact from acidification.

“The shellfish industry recognizes the consequences of ocean acidification for people today, people in this lifetime, and for future generations – to a far greater extent than the U.S. public,” said Rebecca Mabardy, a former OSU graduate student and lead author on the study.”The good news is that more than half of the respondents expressed optimism – at least, guarded optimism – for the industry’s ability to adapt to acidification.

The mechanisms causing ocean acidification are complex, and few in the shellfish industry initially understood the science behind the issue, said OSU marine ecologist George Waldbusser, who has worked with Northwest oyster growers on mitigating the effects of ocean acidification. However, he added, many have developed a rather sophisticated understanding of the basic concepts of carbon dioxide impacts on the ocean and understand the risks to their enterprise.

“Many have seen the negative effects of acidified water on the survival of their juvenile oysters — and those who have experienced a direct impact obviously have a higher degree of concern about the issue,” Waldbusser pointed out. “Others are anticipating the effects of acidification and want to know just what will happen, and how long the impacts may last.

It’s been called the “evil twin” of climate change. As the oceans absorb carbon dioxide from the atmosphere and surface waters become more acidic, changes to marine ecosystems are likely to follow. Coral reefs, shell-forming organisms and the fish and marine mammals that depend on them are at risk.

At the May 11 Corvallis Science Pub, George Waldbusser will describe what scientists know about the biological effects of ocean acidification. The Science Pub presentation is free and open to the public. It begins at 6 p.m. at the Old World Deli, 341 S.W. 2nd St. in Corvallis.

On average, the oceans are about 30 percent more acidic today than they were a century ago, and impacts are already being seen along the West Coast. Waldbusser and his students have turned their attention to the region’s oyster industry, which had $73 million in sales in 2009.

Oyster larvae are sensitive to acidification and Waldbusser, an assistant professor in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences, is working to understand why.

“With larval oysters, what we see are developmental issues,” he said. “From the time eggs are fertilized, Pacific oyster larvae will precipitate roughly 90 percent of their body weight as a calcium carbonate shell within 48 hours.”

His research has been supported by the National Oceanic and Atmospheric Administration, the U.S. Department of Agriculture, Oregon Sea Grant and other agencies.

For years, research into West Coast oyster hatchery die-offs has pointed the finger at Vibrio tubiashii. Now Oregon State University researchers believe a different, but related, bacterium – V. coralliilyticus – may be the real culprit.

The findings were published in Applied and Environmental Microbiology, by researchers from OSU’s College of Veterinary Medicine, the U.S. Department of Agriculture, and Rutgers University. The research was supported by the USDA.

“These bacteria are very similar, they’re close cousins,” said Claudia Häse, an OSU associate professor and expert in microbial pathogenesis. “V. coralliilyticus was believed to primarily infect warm water corals and contributes to coral bleaching around the world. It shares some gene sequences with V. tubiashii, but when we finally were able to compare the entire genomes, it became apparent that most of what we’re dealing with in the Pacific Northwest is V. coralliilyticus.”

Scientists now say that V. coralliilyticus is not only far more widespread than previously believed, but that it can infect a variety of fish, shellfish and oysters, including rainbow trout and larval brine shrimp. And it appears to be the primary offender in bacterial attacks on Pacific Northwest oyster larvae.

Häse’s previous work with Chris Langdon of OSU’s Molluscan Broodstock Lab has been supported in part by Oregon Sea Grant, which has also worked with Northwest shellfish growers to help them rebound from oyster die-offs. By learning to counter the effects of increasingly acidic seawater, which prevents larval oysters from forming the shells they need to survive, many hatcheries have seen production return.

But while hatchery stocks are recovering, the scientists say bacterial infections remain a real problem for oysters – and other organisms – in the wild.

“Although we’ve largely addressed the problems the hatcheries face, these bacteria continue to pose threats to wild oysters,” Häse said. “And corals are still declining in many places, the Great Barrier Reef in Australia is dying at an alarming rate. Better diagnostics might help in all of these situations.”

Posted by: Dylan McDowell | November 7, 2014 Comments Off on Bivalves on drugs: What goes in the water winds up in shellfish |

Bivalves such as oysters assimilate environmental toxins into their body when filtering water.

What happens to an oyster on antidepressants? What about on caffeine? Or, what if you combine these contradictory drugs and then consume the oyster?

As odd as it sounds, this scenario is playing out along the Oregon coast where oysters and other bivalves—a staple food source for both humans and animals— are assimilating low levels of environmental contaminants into their body. Portland State University researcher Elise Granek and colleagues are studying which chemicals are present, where, and what the effects may be up the food chain.

“The work in our lab is looking at how land based contaminants are affecting marine and coastal animals.” Granek said. “In the long term, what are the effects on humans?”

Bivalves—two-shelled animals such as clams, mussels and oysters—are integral to coastlines for food and structure. Not only do they serve as prime dining for many animals, but their colonies also provide shelter for small fish and invertebrates to hide. Bivalves filter water to feed, and thereby ingest a variety of chemicals from the water.

Granek and her team sampled native oysters at two sites along the Oregon coast to get an idea of what chemicals were present in their tissues. The results were stunning: ibuprofen, anti-inflammatory drugs, antihistamine and more. While each of these drugs was present in levels not considered harmful to humans, Granek is concerned about what the combined impact might be.

“These organisms don’t just have one compound. They have 2, 3, 4 types in them,” she explained. “So what happens when you have multiple of these compounds in one organism? How does that affect that organism or how does it affect predators that eat them, including us? We just don’t know.”

These contaminants likely seep into the water from outdated septic tanks or sewer overflows during storms and other high-water events.

Back in the lab, the team is conducting 90-day controlled experiments on each drug to get a better idea of the physiological effects on the bivalves. After they create a baseline for individual drugs—as early as spring—the lab will start combining different drugs to assess the effects.

“Most people who use pharmaceuticals or personal care products may not have any knowledge that what goes down the drain could harm aquatic and marine life,” said Joey Peters, a graduate student conducting the lab experiments. “I hope the results of this project elucidate one small piece of a growing problem.”

The next step is going back into the field to monitor which chemicals are present in other bivalves. From there, Granek wants to begin evaluating human impacts of eating these contaminated species. That information, she says, will help inform policy.

“My perspective has changed since I had a kid, and I think about all of the contaminants that she is exposed to in our world. Some things are harder to control and some things are easier to control. Food ought to be something that is easier to convince policy makers and managers to protect.”

The Whiskey Creek Shellfish Hatchery on the state’s north coast watched oyster larvae die en masse for three years in a row in the mid-2000s — depriving oyster farms along the entire West Coast of seed oysters.

Florence crabber Al Pazar saw baby octopuses, an inch or two long, climb up his crab lines to escape the sea waters in the 2005 season. When he pulled up his pots, the crab were dead.

Eugene fisherman Ryan Rogers, who drags in great piles of salmon on an Alaska purse seiner, has instead brought up nets full of jellyfish in recent years.

“Sometimes we’ll catch 4,000 or 5,000 pounds of jellyfish. They spray all around. We get stung,” he said. “It makes it difficult to bring your net in. You have to let it go and lose the salmon that are in your net.”

Scientists — including many at Oregon State University — are beginning to define the cause of these events. They call it ocean acidification and hypoxia.

Wind, currents and ocean chemistry conspire to create pools of corrosive waters that can be lethal to key commercial species in Northwest waters — and favorable to some nuisance species, such as jellyfish. …

The Eugene Register-Guard examines what OSU scientists – some of them working with Oregon Sea Grant funding – are learning about the causes and consequences of ocean acidification.

COOS BAY – While some West coast oyster stocks are threatened by rising ocean acidity, native oysters on Oregon’s south coast seem to be doing well.

Netarts Bay’s Whiskey Creek Shellfish Hatchery — which produces much of the oyster seed used by commercial farms in the region —has experienced a decline in production that Oregon State University researchers traced directly to ocean acidification.

But biologist Steve Rumrill, director of the Oregon Department of Fish and Wildlife shellfish monitoring program at the South Slough National Estuarine Research Reserve, suspects that the shallow parts of Coos Bay “may be able to act as a sort of buffer,” protecting native Olympia oysters in that area from the shell-destroying effects of ocean acidification.

Another clue could lie in the oysters’ breeding habits, according to George Waldbusser, an OSU biologist who studies oyster reproduction and survival.

“Olympias are brooders,” Waldbusser said, referring to the species’ trait of carrying eggs in an internal chamber for several weeks after fertilization, whereas the Pacific oysters bred in Netarts Bay broadcast their fertilized eggs into the open water, where they are directly exposed to chemical changes at an earlier point in their life cycles, when they may be more vulnerable.

Oregon State University will receive funds that will help the West Coast’s shellfish industry in its fight against ocean acidification, thanks largely to the efforts of Oregon state Senator Betsy Johnson (D-Scappoose). Receipt of these funds will give a critical boost to Oregon State University’s and the shellfish industry’s efforts to reduce the negative impacts of ocean acidification on shellfish production.

House Bill 5008 allocated $250,000 to Oregon State University. A portion of the funds will be used to continue OSU’s efforts to improve the resilience of oyster to ocean acidification through its selective breeding program at the Hatfield Marine Science Center in Newport. The remaining funds will be dedicated to OSU’s collaboration with industry leaders at the Whiskey Creek Shellfish Hatchery (see “The Whiskey Creek Shellfish Acid Tests” in the current issue of Confluence) on Netarts Bay as they continue to identify better ways to manage the negative effects of ocean acidification on shellfish larvae.